While blacks comprise 28 percent of Oakland's population, they accounted for 62 percent of nearly 15,000 police stops during an eight-month period, according to the preliminary report. Hispanics were the next highest at 17 percent followed by whites at 12 percent.
Asians and other groups comprised 9 percent.
Most of the stops were due to traffic violations, but blacks had the lowest percentage 54 percent, compared to Asians, 76 percent. Blacks, however, had the highest percentage of being stopped due to probable cause and reasonable suspicion.
The information was collected between April and November of last year.
The report had been ordered by a federally appointed monitor as part of court-mandated reforms to settle a multimillion-dollar lawsuit alleging widespread misconduct in the aftermath of the Riders police brutality scandal more than a decade ago.
Attorney John Burris, one of two lawyers who represented the plaintiffs in the case who's also overseeing the still yet-to-be-completed reforms, said Monday that he was disappointed but not surprised by the disproportionate number of blacks stopped by police.
"There's a long-held belief in the African-American community that they were being stopped without reasonable suspicion and they were being searched,'' Burris said. "This is just a drop in the bucket and we only have six months' worth of data. We've been trying to get this type of information for over a decade. This is the first step in a long process of rooting out these issues related to racial profiling.''
The report said that while blacks were more likely to be searched by police after they were stopped, officers were no more likely to recover contraband from them than from any other ethnic group. The searches resulted in contraband being found 27 percent of the time for blacks and Hispanics compared to whites and Asians at 27 and 25 percent, respectively.
The report also comes out at a time when police departments such as New York City, are undergoing reforms to its controversial stop-and-frisk policy, a practice allows police to stop, question and pat down anyone who appears suspicious. Critics say it can lead to racial profiling and civil rights violations.
New York City Police Commissioner Bill Bratton, a onetime consultant to the Oakland Police, has said New York's policy was overused and created a negative reaction.
Interim Oakland Police Chief Sean Whent reiterated in a statement Monday that the department adopted a policy in 2004 that prohibiting racial profiling and any bias-based policing. He said the data taken last year was done to create more accountability and transparency.
"As the report illustrates, police officers stop people of color with the highest frequency. Unfortunately this is the situation in many U.S. cities and speaks to the need for systemic changes throughout our communities,'' Whent said. "We are committed to working toward an Oakland that ensures equal opportunities, protections and successes for all.''
The data also comes out at time when the department is working to reduce crime and rebuild public trust in one of the most dangerous cities in America, said Frank Zimring, a law professor at the University of California, Berkeley.
"This is a real dilemma, because on one hand there's no evidence that the police are using anything other than crime- controlled criteria to select the targets for their stops, but on the other hand, most of the people they stop are African-Americans,'' Zimring said. "There is no clean `Everybody wins,' solution to this.''